Risk Factors Associated With Circumferential Resection Margin Positivity in Rectal Cancer: A Binational Registry Study.

Abstract

Rectal cancer outcomes have improved with the adoption of a multidisciplinary model of care. However, there is a spectrum of quality when viewed from a national perspective, as highlighted by the Consortium for Optimizing the Treatment of Rectal Cancer data on rectal cancer care in the United States. The aim of this study was to assess and identify predictors of circumferential resection margin involvement for rectal cancer across Australasia. A retrospective study from a prospectively maintained binational colorectal cancer database was interrogated. This study is based on a binational colorectal cancer audit database. Clinical information on all consecutive resected rectal cancer cases recorded in the registry from 2007 to 2016 was retrieved, collated, and analyzed. The primary outcome measure was positive circumferential resection margin, measured as a resection margin ≤1 mm. A total of 3367 patients were included, with 261 (7.5%) having a positive circumferential resection margin. After adjusting for hospital and surgeon volume, hierarchical logistic regression analysis identified a 6-variable model encompassing the independent predictors, including urgent operation, abdominoperineal resection, open technique, low rectal cancer, T3 to T4, and N1 to N2. The accuracy of the model was 92.3%, with an receiver operating characteristic of 0.783 (p < 0.0001). The quantitative risk associated with circumferential resection margin positivity ranged from <1% (no risk factors) to 43% (6 risk factors). This study was limited by the lack of recorded long-term outcomes associated with circumferential resection margin positivity. The rate of circumferential resection margin involvement in patients undergoing rectal cancer resection in Australasia is low and is influenced by a number of factors. Risk stratification of outcome is important with the increasing demand for publicly accessible quality data. See Video Abstract at http://links.lww.com/DCR/A512.